$9mn + 8mp + 8m + 2 = 2n - 9$ Solve for $m$.
Combine constant terms on the right. $9mn + 8mp + 8m + {2} = 2n - {9}$ $9mn + 8mp + 8m = 2n - {11}$ Notice that all the terms on the left-hand side of the equation have $m$ in them. $9{m}n + 8{m}p + 8{m} = 2n - 11$ Factor out the $m$ ${m} \cdot \left( 9n + 8p + 8 \right) = 2n - 11$ Isolate the $m$ $m \cdot \left( {9n + 8p + 8} \right) = 2n - 11$ $m = \dfrac{ 2n - 11 }{ {9n + 8p + 8} }$